HU226483B1 - Lipid nanocapsules, preparation method and use as medicine - Google Patents

Description

BACKGROUND OF THE INVENTION The present invention relates to lipidnano capsules, their preparation and, more particularly, to the use of a pharmaceutical composition for injection, oral or nasal administration.

In recent years, a number of research groups have focused on the development of solid lipid nanoparticles and lipid nanoparticles [Müller, R.H. and Mehnert, European Journal of Pharmaceutics and Biopharmaceutics; 41 (1): 62-69 (1995); W., Gasco, M.R.: Parmaceutical Technology Europe; 52-57 (1997); EP 605 497] These are an alternative to the use of liposomes and polymeric particles. The advantage of lipid particles is that they can be formed without solvent. Both lipophilic and hydrophilic products can be encapsulated in ionic pairs [e.g., Cavalli, R., et al., S. T. P. Pharma Sciences; 2 (6): 514-518 (1992); and Cavalli, R., et al., International Journal of Pharmateutics; 117: 243-246 (1995)]. These particles are stable for several years at 8 ° C when protected from light [Freitas, C. and Müller, R.H., Journal of Microencapsulation; 1 (16): 59-71 (1999)].

There are two commonly used methods for preparing lipidnano particles:

hot emulsion (Schwarz, C., et al., Journal of Controlled Release; 30: 83-96 (1994); Müller, R.H., et al., European Journal of Pharmacy and Biopharmateutics; 41 (1), 62-69 (1995)] or cold emulsion (Mühlen, A. and Mehnert, W., Pharmazie; 53: 552-555 (1998); EP 605 497], or

sudden cooling of the microemulsion in the presence of a cosurfactant such as butanol, wherein the nanoparticles produced are generally at least 100 nm in size [Cavalli, R., et al., European Journal of Pharmacy and Biopharmateutics; 43 (2): 110-115 (1996); Morei, S., et al., International Journal of Pharmateutics; 132: 259-261 (1996).

Cavalli et al., International Journal of Pharmateutics; 2 (6), 514-518 (1992) and Pharmazie; 53, 392-396 (1998)] reported the injection of a non-toxic bile salt, taurodeoxycholate, into nanospheres of 55 nm or larger by injection.

French Patent No. 2,692,167 discloses the preparation of nanocapsules having a mean size of 100 nm to 900 nm (page 1, line 5) and optionally containing an oil core containing an active molecule (page 3, lines 20-23). , the wall of which is coated with modified cyclodextrin. Thus, the walls of these nanocapsules are essentially non-lipid.

U.S. Patent No. 5,049,322 discloses the preparation of nanocapsules having a mean size of less than 500 nm and containing a substance B coated with a wall containing substance A. Preferably, the material is a synthetic or natural polymer. Lipid Type B is not mentioned in this document.

U.S. Patent No. 5,174,930 is a continuation of the above-mentioned U.S. Patent No. 5,049,322 (Continuation-inPart). This document describes oligolamellar liposomes containing:

a seed comprising water and an aqueous solution;

- a wall containing amphiphilic lipids.

Nanocapsules containing essentially a lipid core have not been disclosed in this document.

European Patent 0 717 989 discloses the preparation of coating droplets or particles comprising chemically or biologically active substances together with one or more biocompatible polymers. Coating lipid material is not mentioned in this document,

European Patent 0 529 711 discloses the preparation of nanospheres, nanoparticles, or nanocapsules having a medium-sized lipid core of between 50 nm and 5000 nm (page 3, lines 12-15). The coating of the resulting colloidal system contains a polymer or a biocompatible monomer (page 3, lines 16-28). Lipid material as a coating is not mentioned in this document.

European Patent 0 447 318 discloses cosmetic or pharmaceutical compositions containing biodegradable polymeric nanocapsules containing a carrier and an active ingredient, wherein the active ingredient is oily in nature or in oil. No lipid material for use as a nanocapsule wall is mentioned in this document.

European Patent 0 621 073 discloses a process for increasing the stability of nanocapsules by lyophilization (page 3, lines 21-22). These nanocapsules contain a lipid core with a polymer wall (pages 5-13). No lipid material for use as a wall is mentioned in this document.

None of the above documents discloses a process involving a phase inversion step in which the temperature is raised above the phase inversion temperature (PIT) and then reduced to a T? PIT temperature.

The present invention relates to nanocapsules and not to nanospheres. By "nanocapsule" is meant a core containing particles that are liquid or semi-liquid at room temperature and are coated with a solid film, whereas nanospheres are matrix particles, i.e., particles whose total mass is solid. When the nanospheres contain a pharmaceutically active substance, the active ingredient is finely dispersed in the solid matrix.

In the context of the present invention, the term "room temperature" refers to a temperature between 15 ° C and 25 ° C.

The present invention relates to nanocapsules having an average size of less than 150 nm, preferably less than 100 nm, and more preferably less than 50 nm. Each nanoparticle contains a substantially liquid core that is liquid or semi-solid at room temperature and is coated with a lipid film that is substantially solid at room temperature.

In terms of size, the nanocapsules of the present invention are colloidal lipid particles.

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The polydispersity index of the nanocapsules of the invention is preferably between 5% and 15%.

The thickness of the solid film is preferably between 2 nm and 10 nm. It is also about one tenth of the diameter of the particles.

The core of the nanoparticles consists essentially of a fatty material which is liquid or semi-liquid at room temperature, for example a triglyceride or a fatty acid ester containing from 20% to 60% by weight, preferably 25% to 50% by weight of the nanocapsules. It is formed.

Preferably, the solid film coating the nanocapsules consists essentially of a lipophilic surfactant such as lecithin having a phosphatidylcholine moiety of between 40% and 80%. The film may also contain a hydrophilic surfactant such as Solutol® HS 15.

The hydrophilic surfactant in the solid film coating the nanocapsules preferably comprises between 2% and 10% by weight, preferably 8% by weight, of the nanocapsule.

The triglyceride that forms the core of the nanocapsules is preferably C8-C12, for example, triglyceride of capric or caprylic acid, or mixtures thereof.

The fatty acid ester is a C 8 -C 18 fatty acid ester such as ethyl palmitate, ethyl oleate, ethyl myristate, isopropyl myristate, octadodecyl myristate or a mixture thereof. Preferably the fatty acid ester has from 8 to 12 carbon atoms.

The nanocapsules of the present invention are particularly suitable for formulating pharmaceutical agents. In this case, the lipophilic surfactant is preferably solid at 20 ° C and liquid at about 37 ° C.

The amount of lipophilic surfactant in the solid film coating the nanocapsules corresponds to a weight ratio of liquid to fatty solid / solid surfactant of from 1 to 15, preferably from 1.5 to 13, more preferably from 3 to 8.

The present invention also provides a process for making the nanocapsules described above.

The process of the present invention is based on an oil / water emulsion phase inversion which is carried out in several cycles of temperature increase and reduction.

The process of the present invention comprises:

a) - Preparation of an oil-in-water emulsion comprising an oily fatty phase, a nonionic hydrophilic surfactant, a solid lipophilic surfactant at 20 ° C and optionally an aqueous active ingredient soluble or dispersible in the oily fatty phase or an aqueous contains phase-soluble or dispersible pharmaceutical active ingredient,

- the phase inversion of said oil / water emulsion is carried out by raising the temperature to T ₂ above the phase inversion temperature (PIT) to produce a water / oil emulsion and then lowering the temperature to T ·, where T ^ PIT * ^,

- performing at least one additional temperature cycle between the phase inversion zone T ₁ and T _{2 until} a clear suspension is formed,

b) cooling the oil / water emulsion to a temperature close to T,, preferably above T,, to form stable nanocapsules.

Preferably, the nanoparticles produced by the process of the present invention do not contain surfactants such as C 1-4 alcohols.

The number of cycles used in the emulsion depends on the amount of energy required to produce the nanocapsules.

Phase inversion can be detected by the loss of conversion conductivity during formation of the water / oil emulsion.

The process of the present invention consists of two steps.

In Step 1, all ingredients are weighed, heated to a temperature above T ₂ with slow stirring (e.g., magnetic stirring) and optionally cooled to T 1 (T 4). A water / oil emulsion is formed after a certain number of temperature cycles.

The phase inversion between the oil / water emulsion and the water / oil emulsion is shown by a decrease in conductivity as the temperature rises until it disappears. The average temperature of the phase inversion zone corresponds to the phase inversion temperature (PIT). The organization of the system in the form of nanocapsules is reflected by a change in the appearance of the initial system, which changes from opaque white to transparent white. This change occurs at temperatures below the PIT temperature. This temperature is generally 6-15 ° C below the PIT temperature.

T ₁ is the temperature at which the conductivity is equal to at least 90-95% of the conductivity measured at 20 ° C.

T ₂ is the temperature at which the conductivity ceases.

In step 2, the oil / water emulsion is cooled (or frozen) to about T1, preferably above T1, under magnetic stirring, whereby the fine emulsion is added at a rate of 3 to 10 times the amount of deionized water at 2 ± 1 ° C. The resulting particles were further stirred for 5 minutes.

In a preferred embodiment, the fatty phase is a fatty acid triglyceride, a solid lipophilic surfactant lecithin and a hydrophilic surfactant Solutos® HS 15. Under these conditions, Τ _Ί = 60 ° C, T ₂ = 85 ° C and the number of cycles is 3.

The liquid to solid surfactant ratio is from 1 to 15, preferably from 1.5 to 13, and more preferably from 3 to 8.

Preferably, the oil / water emulsion comprises from 1% to 3% by weight of a lipophilic surfactant, from 5% to 15% by weight of a hydrophilic surfactant, from 5% to 15% by weight of an oily fatty substance and from 64% to 89% by weight % water.

The higher the HLB value of the liquid fatty material, the higher the phase inversion temperature. On the other hand, the HLB value of the fatty material does not appear to affect the size of the nanocapsules.

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Thus, as the triglyceride end groups increase in size, their HLB values decrease and the phase inversion temperature decreases.

HLB or hydrophilic / lipophilic equilibrium is determined according to Larpent, C., Treatise K.342 of Editions, Techniques de l'ngniur.

The particle size decreases as the proportion of hydrophilic surfactant increases and as the ratio of surfactant (hydrophilic and lipophilic) increases. In particular, the surfactant contributes to the reduction of the interfacial tension and thus to the stabilization of the system, which causes the formation of small particles.

In addition, as the particle size increases, the proportion of oil increases.

In a preferred embodiment of the invention, the fatty phase is Labrafac® WL 1349, the lipophilic surfactant Lipoid® S75-3 and the non-ionic hydrophilic surfactant Solutol® HS 15. These compounds have the following characteristics:

Labrafac® lipophilic WL 1349 (Gattefossé, SaintPriest, France): an oil consisting of caprylic and capric acid medium C 8 -C 10 triglycerides having a density at 20 ° C of 0.930 to 0.960 and an HLB of about 1;

Lipoid® S75-3 (Lipoid GmbH, Ludwigshafen, Germany): corresponds to soybean lecithin, soybean lecithin contains about 69% phosphatidylcholine and 9% phosphatidylethanolamine, these are surfactants and this ingredient is the only ingredient an ingredient which is solid at 37 ° C and at room temperature and is widely used to form injectable particles;

Solutol® HS 15 (BASF, Ludwigshafen, Germany): polyethylene glycol-660-2-hydroxystearate, behaves as a nonionic hydrophilic surfactant in the formulation, for injection (LD ₅₀ > 3.16 g / kg i.v. in rats) 1.0 <LD ₅₀ <1.47 g / kg).

The aqueous phase of the oil / water emulsion may also contain from 1% to 4% of salts, for example sodium chloride. By changing the salt concentration, the phase inversion zone is shifted. The higher the salt concentration, the lower the phase inversion temperature. This phenomenon is advantageous when encapsulating hydrophobic thermosensitive agents, since it can be performed at lower temperatures.

The nanocapsules of the present invention preferably contain an active ingredient and can be used for injection, in particular intravenous injection, orally or nasally.

When the active ingredient is poorly soluble in the oil phase, a co-solvent such as Ν, Ν-dimethylacetamide is added.

The nanoparticles of the present invention are particularly suitable for the administration of the following agents:

- anti-infectious agents such as antifungal agents and antibiotics,

- anticancer agents,

agents for the central nervous system that need to cross the blood-brain barrier, such as anti-Parkinson agents, more generally agents for treating neurodegenerative diseases.

The therapeutically active agent is first dissolved or dispersed in an oily fatty phase, in which case it is incorporated into the core of the nanocapsule. It is then mixed in a first step for the preparation of an oil / water emulsion which also contains the oily fatty phase, a nonionic hydrophilic surfactant and a solid lipophilic surfactant at 20 ° C.

The pharmaceutical agent can also be water-soluble or dispersible in an aqueous phase, in which case it is only fixed on the surface of the nanocapsules after the final phase of the preparation of stable nanocapsules. The water-soluble active ingredient can have any properties such as proteins, peptides, oligonucleotides or DNA plasmids. Such an active ingredient can be anchored on the surface of the nanocapsules by adding said active ingredient to the solution in which the stable nanocapsules obtained by the process of the present invention are dispersed. The presence of a nonionic hydrophilic surfactant promotes the interaction between the water-soluble active ingredient and the free surface of the nanocapsules.

The water-soluble active ingredient may also be added to the aqueous phase during the first step of the starting oil / water composition.

The present invention is illustrated by the following examples, in which Figs. Referring to FIGS.

Figure 1 is a photograph of the nanocapsules of the present invention prepared in Example 1 at a magnification of 50 cm;

Figure 2 shows a change in mean particle size versus hydrophilic surfactant (Solutol®) ratio;

Figure 3 shows the change in conductivity as a function of temperature at different salt concentrations, with curve 1 having a salt concentration of 2.0 wt%,

Curve 2 has a salt concentration of 3.4% by weight;

Figure 4 shows the change in conductivity, the change in the conductivity of the oil / water (O / W) emulsion of Example 1, after three cycles of temperature increase and reduction between 60 ° C and 85 ° C.

Example 1

Non-Active Nanocapsules A. Preparation of Nanocapsules A 5 g emulsion is prepared containing 75 mg Lipoid® S75-3,504 mg Labrafac® WL 1349 lipophilic, 504 mg Solutol® HS 15, 3,829 g water and 88 mg sodium chloride .

The ingredients are poured into the same beaker and mixed with a magnetic stirrer. The system was heated to 85 ° C and allowed to cool to 60 ° C with magnetic stirrer.

HU 226 483 Β1 beat. This cycle is performed between 85 ° C and 60 ° C, until the loss of conductivity as a function of temperature is observed, as shown in Figure 4. Phase inversion occurs after cycle 3. On final cooling, 12.5 ml of distilled water at 2 ± 1 ° C is added to the mixture at 70 ° C and frozen. The system is then stirred for 5 minutes with a magnetic stirrer.

The particles produced under the conditions described above have an average size of 43 ± 7 nm in 3 temperature cycles. Their polydispersity is 0.071. Transmission electron microscopy using phosphorus tungstic acid can detect medium-sized particles of about 50 nm, as shown in Figure 1. In addition, nanocapsules were found to be really solid at 25 ° C by atomic microscopy (Park Scientific Instruments, Geneva, Switzerland).

B) Changing the ratio of hydrophilic surfactant

Table 1 below shows formulations of nanocapsules prepared at different concentrations of hydrophilic surfactant.

Table 1

Crowd% Lipoid S75-3 1.51 1.51 1.51 1.51 1.51 1.51 1.51 1.51 Labrafac® WL 1349 10.08 10.08 10.08 10.08 10.08 10.08 10.08 10.08 Solutol® HS 15 5.00 7.50 10.08 15.00 20.00 22.50 25.00 30.00 Water 84.65 79.10 76.60 71,68 66.68 61.18 61.68 56.68 Nazi 1.76 1.76 1.76 1.76 1.76 1.76 1.76 1.76

Decreasing Solutol® HS 15 concentration increases the mean particle size as shown in Figure 2. Accordingly, a change in the mean size from 23 nm to 128 nm is observed by decreasing the Solutol® fraction from 30% to 5% (relative to the total formulation), respectively. Thus, the size depends on the hydrophilic surfactant concentration.

C) Change in the proportion of Lipoid® and Solutol® surfactants

Table 2 below shows formulations containing nanocapsules prepared at different surfactant concentrations. 35

Table 2

Crowd% THE B C Lipoid S75-3 0.78 1.51 2.35 Labrafac® WL 1349 10.08 10.08 10.08 Solutol® HS 15 5.22 10.08 15.65 Water 82.16 76.60 10.16 Nazi 1.76 1.76 1.76 Surfactant Ratio (Lipoid S75-3 + Solutol® HS 15) 6.00 11.59 18,00

Medium size decreases with increasing surfactant ratio. Specifically, formulation A yields 85 ± 7 nm medium size particles (P = 0.124). Medium sizes for formulations B and C were 43 ± 7 nm (P = 0.071) and 29 ± 8 nm (P = 0.148), respectively.

D) Change in sodium chloride concentration

Table 3 below shows two formulations of nanocapsules prepared at different concentrations of sodium chloride.

Table 3

Crowd% Lipoid S75-3 1.73 1.70 Labrafac® WL 1349 5.76 2.84 Solutol® HS 15 2.88 5.68 Water 87.61 86.36 Nazi 2.02 3.40

As the salt concentration changes, the phase inversion zone shifts. The higher the salt concentration, the lower the phase inversion temperature as shown in Figure 3. This phenomenon may be advantageous for encapsulation of heat-sensitive hydrophobic active ingredients since they can be mixed at low temperatures.

With these formulations, particles of similar size can be prepared at different salt concentrations.

Example 2

Encapsulation of Sudan III lipophilic drug

The composition corresponds to that of Example 1: 5 g of starting emulsion were prepared: 75 mg Lipoid® S75-3, 504 mg Labrafac® lipophilic and 504 mg Solutol® HS 15,

By weighing 3.829 g water and 88 mg sodium chloride.

200 mg of Sudan III dissolved in liquid petroleum gel are added. The mixture is weighed into the same beaker and stirred with a magnetic stirrer. Heat to 85 ° C. The system was then allowed to cool to 60 ° C while stirring with a magnetic stirrer. This cycle is repeated 3 times between 85 ° C and 60 ° C. On the final cooling, 12.5 ml of distilled water at 2 ± 1 ° C is frozen from 70 ° C. The system is then agitated with a magnetic ke60 beater for 5 minutes.

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Sudan III encapsulates particles of a size similar to that of Example 1 using the same surfactant to fatty phase ratio of 45 + 12 nm (P = 0.138). With the naked eye, the patterns look even pink. 5

Example 3

Encapsulation of Progesterone

The formulation corresponds to Example 1: 5 g of starting emulsion are prepared with 75 mg of Lipoid® S75-3,

Labrazac® is lipophilic (504 mg) and Solutol (504 mg), water (3.829 g) and sodium chloride (88 mg) are added with 10 mg of prasteresterone. The mixture is weighed into the same beaker and stirred with a magnetic stirrer. Heat to 85 ° C. The system was then allowed to cool to 60 ° C while stirring with a magnetic stirrer. This cycle is repeated three times between 85 ° C and 60 ° C.

On final cooling, add 12.5 ml of distilled water at 2 ± 1 ° C from 70 ° C. The system is then stirred with a magnetic stirrer for 5 minutes.

By encapsulating progesterone, a particle size similar to that of Example 1 was obtained which was 45 ± 12 nm (P = 0.112). No concentration of progesterone was found in the aqueous phase above its solubility. More specifically, centrifugation at 200,000 rpm for 30 minutes gave a clear precipitate, the composition of which was examined by DSC. This precipitate does not contain progesterone. Because progesterone is visibly insoluble in water, this indicates that the active ingredient is present in the nanocapsules.

Example 4

Encapsulation of Busulfan suspension

A) Busulfan suspension at 0.25 mg / ml

Busulfan is dissolved in N, N-dimethylacetamide in the first step of encapsulation. Thus, a solution containing 24 mg of busulfan per ml of N, N-dimethylacetamide was prepared. 175 mg of this solution is added to 504 mg of Labrafac®. Weigh out 75 mg of Lipoid® S75-3,

504 mg of Solutol®, 3,829 water and 88 mg of sodium chloride. (i.e., a starting emulsion concentration of 0.88 mg / g. The ingredients are mixed in the same beaker and stirred with a magnetic stirrer. Heat to 85 ° C. The system is allowed to cool to 60 ° C and is stirred with a magnetic stirrer. This cycle is 85 ° Repeat this process 3 times between C and 60 ° C. The final cooling is carried out by freezing at 70 ° C with 12.5 ml of distilled water at 2 ± 1 ° C. The system is then stirred with a magnetic stirrer for 5 minutes. after dilution 0.25 mg / ml.

The resulting particles are slightly larger in size

In Example 1, because the ratio of the fatty phase is higher (63 ± 5 nm). Concerning progesterone, busulfan was not present in the aqueous phase at concentrations above its solubility. In particular, no crystals are visible in the aqueous phase after encapsulation as determined by optical microscopy. Because busulfan is visibly insoluble in water, this indicates that busulfan is present in the nanocapsules.

B) Busulfan suspension at a concentration of 0.50 mg / ml

A particle suspension of 0.50 mg / L was prepared by dissolving 50 mg of busulfan in 1 ml of N, N-dimethylacetamide under the same conditions. To 175 mg of this solution was added 504 mg of Labrafac®. 75 mg of Lipoid® S75-3, 504 mg of Solutol®, 3.829 g of water and 88 mg of sodium chloride are also weighed. Thus, the initial emulsion concentration is 1.76 mg / ml. The ingredients are mixed in the same beaker and mixed with a magnetic stirrer. Heat to 85 ° C. The system was allowed to cool to 60 ° C while stirring with a magnetic stirrer. This cycle is repeated three times between 85 ° C and 60 ° C. On final cooling, 12.5 ml of distilled water at 2 ± 1 ° C is frozen from 70 ° C. The system is then stirred for 5 minutes with a magnetic stirrer. The final concentration after freezing, i.e. dilution, is 0.50 mg / ml.

Example 5

Effect of the property of the fatty substance on the phase inversion temperature Labrafac®, an oil containing capric and caprylic triglycerides, is compared with fatty acid esters. The effect of the size of the end groups on the phase inversion temperature can be demonstrated. It is observed that the phase inversion temperature increases with the size of the groups. Thus, the change in appearance in the myristate series is for the ethyl ester seen at 69.5 ° C, the isopropyl ester seen at 71.5 ° C and the octyl dodecyl ester seen at 86.5 ° C. This increase means that the oil-in-water emulsion is formed much faster when the oil has a lower HLB (more lipophilic). In particular, this more pronounced lipophilic property enhances the hydrophobic bond between the surfactant and the oil, and thus requires more energy to invert this system. In addition, the length of the fatty acid carbon chain does not affect the particle size and phase inversion temperature for carbon atoms from 14 to 18 carbon atoms. However, the double bond present in ethyl oleate seems to significantly increase the phase inversion temperature.

The results are shown in the table below.

Table 4

oils carbon number (fatty acid) Double knitting Appearance change temperature (° C) particle Size (Nm) Labrafac®, lipophilic 8/10 0 77.0 43 ± 7 Ethyl palmitate 16 0 69.0 37 ± 15

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Table 4 (continued)

oils carbon number (fatty acid) Double knitting Appearance change temperature (° C) particle Size (Nm) Ethyl oleate 18 1 71.5 41 ± 5 Ethyl myristate 14 0 69.5 35 ± 13 Isopropyl myristate 14 0 71.5 44 ± 23 Ektil-decyl myristate 14 0 86.0 42 ± 16

It seems that the HLB value of the fatty substance does not significantly influence the particle size.

Example 6

Effect of the property of the lipophilic surfactant on the size of the nanocapsules Different types of lecithins are used which have a phosphatidylcholine ratio of between 40% and 90%. The average particle size increases with the phosphatidylcholine content in lecithin as shown in Table 5. Specifically, for 40% phosphatidylcholine, the nanocapsules have a size of 35 ± 8 nm, but when the lecithin has a phosphatidylcholine ratio of 75% and 90%, the size 25 is 43 ± 7 nm or 78 ± 12 nm, respectively. On the other hand, using charged molecules, no nanocapsules can be formed.

Table 5

Lipoid type Phosphatidylcholine drink (%) Medium particle size (nm) Lipoid S45 40 35 ± 8 Lipoid S75-3 69 43 ± 7 Lipoid S100 90 78 ± 12 Lipoid EPC 98 61 ± 12 Lipoid E80 80 72 ± 18

Example 1

Lipidnano capsules with a water-soluble active ingredient attached to their surface

500 mg of the dispersion of lipidnanocapsule according to Example 1, which contains no active ingredient and which has the following composition:

- Lipoid® S75-3: 1.51% by weight - Labrafac® W1.1349: 10.08% by weight -Solutol® HS 15: 10.08% by weight -Water: 76.6% by weight - NaCI: 1.76% by weight The lipidnano capsules produced were 43 ± 7 nm in size.

mg of the lipidnanocapsule dispersion thus prepared was diluted with 1 ml of water and incubated with gentle agitation in an aqueous solution containing 50 g of DNA (pSV β-galactosidase, Promega, France) for 1 hour in the presence of a mixture of histones obtained from calf thymus (Boehringann Mann). , Germany). Thus, lipidnanocapsules containing DNA molecules condensed on their surface and adsorbed on their surface are prepared. 60

Claims (21)

A nanocapsule having an average size of less than 150 nm, preferably less than 100 nm, and more preferably less than 50 nm, consisting essentially of a lipid core which is liquid at room temperature or semi-liquid and is substantially coated with a lipid film which is solid at room temperature. The lipidnano capsule of claim 1 having a polydispersity index of between 5% and 15%. The lipidnano capsule according to claim 1 or 2, wherein the solid film has a thickness of between 2 nm and 10 nm. 4. A lipid nanocapsule according to any one of claims 1 to 5, wherein the core contains a substantially fatty substance, such as triglyceride or fatty acid ester, in a proportion of 20 to 60% by weight, preferably 25 to 50% by weight, of the nanocapsule. The lipidnano capsule according to claim 4, wherein the triglyceride constituting the core of the nanocapsule is a C8-C12 triglyceride, which is a triglyceride of capric acid or caprylic acid, or a mixture thereof. The lipidnanocapsule according to claim 4, wherein the fatty acid ester forming the core of the nanocapsule is a C 8 -C 18 fatty acid ester, namely ethyl palmitate, ethyl oleate, ethyl myristate, isopropyl myristate and octyldodecyl myristate, or a mixture thereof. The lipidnanocapsule according to claim 6, wherein the fatty acid ester has from 8 to 12 carbon atoms. 8. A lipidnano capsule according to any one of claims 1 to 5, wherein the solid film consists essentially of a lipophilic surfactant. The nanocapsule according to claim 8, wherein the ratio of fatty material to lipophilic surfactant is between 1 and 15, preferably between 1.5 and 13, more preferably between 3 and 8. The lipidnano capsule according to claim 8 or 9, wherein the lipophilic surfactant is lecithin, wherein the phosphatidylcholine ratio is between 40% and 90%. 11. A lipid nanocapsule according to any one of claims 1 to 6, wherein the solid film further comprises a nonionic hydrophilic surfactant, Solutol (R) HS 15, present in an amount of 2% to 10% by weight of the nanocapsule. 12. A lipidnano capsule according to any one of claims 1 to 6, which comprises a pharmaceutically active substance. HU 226 483 Β1 13. A method of any of claims 1-12. A nanocapsule according to any one of claims 1 to 3, characterized in that: a) - an oil / water emulsion comprising an oily fatty phase, a nonionic hydrophilic surfactant, a solid lipophilic surfactant at 20 ° C and optionally a pharmaceutically active substance soluble or dispersible in the oily fatty phase, or it contains a pharmaceutically active substance soluble or dispersible in the aqueous phase, performing a phase inversion of said oil / water emulsion by raising the temperature to T ₂ above the phase inversion temperature (PIT) to produce a water / oil emulsion and then lowering the temperature to a temperature T ₁ where T.? PIT <T ₂ , - at least one or more is carried out in the temperature cycle T ₂ and phase inversion zone around until a clear suspension b) tempering the oil / water emulsion at a temperature around T ·, preferably above T _r , to form stable nanocapsules. 14. The process according to claim 13, wherein the oily fatty phase is a C8-C12 triglyceride, a capric or caprylic triglyceride or a mixture thereof, or a C8-C18 fatty acid ester, namely ethyl palmitate, ethyl oleate, ethyl myristate, isopropyl myristate or octyldodecyl myristate or a mixture thereof. 15. The process of claim 13 or 14 wherein the nonionic hydrophilic surfactant is Solutol® HS 15. 16. A process according to any one of claims 1 to 3, wherein the lipophilic surfactant is lecithin, wherein the phosphatidylcholine ratio is 40% to 90%, preferably Labrafac® WL 1349. 17. A 13-16. A process according to any one of claims 1 to 4, characterized in that an oil / water emulsion is used which has the following composition in% by weight of the base: 1% to 3% lipophilic surfactant, 5% to 15% hydrophilic surfactant, 5 to 15% oily fatty matter and 64% to 89% water. 18. A 13-17. A process according to any one of claims 1 to 3, characterized in that an oil / water emulsion is used which contains from 1% to 4% of salt, preferably sodium chloride. 19. A process according to any one of claims 1 to 3, characterized in that a lipophilic surfactant is used which is solid at 37 ° C. 20. A 13-19. A process for the preparation of nanocapsules according to any one of claims 1 to 3, characterized in that a water-soluble pharmaceutically active substance is adsorbed onto the free surface of the stable nanocapsule produced in step b). 21. Use of a nanocapsule according to any one of claims 1 to 4 for the preparation of a pharmaceutical composition for injection, preferably by intravenous injection, for oral or nasal administration.